The present invention relates in general to new and useful modified membrane compositions for use in ultrafiltration and microfiltration processes, having advantageous flow characteristics and mechanical strength and to a process for their preparation.
During the past 25 years, ultrafiltration and microfiltration processes have found wide application in such industries as the pharmaceutical, food, automotive, electronic, biotechnology, chemical and dairy industries.
Aryl polysulfone polymers are commonly used by many manufactures to produce ultrafiltration membranes and supports for reverse osmosis membranes prepared by interfacial polymerization. These include U.S. manufacturers such as Amicon Div., W. R. Grace, Mass; Dow Company, Michigan; Gelman Sciences, Inc., Michigan; Millipore Corp., Massachusetts; Osmonico Inc., Minnesota; Koch, Mass; and Pall Corp.
In many applications, these aryl polysulfone membranes, which are relatively hydrophobic in character, are very susceptible to membrane fouling and plugging by dissolved solutes such as proteins or suspended colloids such as latex paint particles. Adsorption of such solutes in the membrane pores can impede and constrict the flow through the membrane and result in diminished performance. By modifying these aryl polysulfone membranes, using the present invention, solute-membrane interactions will be reduced and this results in improved long-term performance. Thus, for example, recovery and purifications of valuable proteins using ultrafiltration would be more efficient when using modified aryl polysulfone membranes of the present invention rather than unmodified commercially available aryl polysulfone membranes.